Electronic meter systems have been developed, as for example the systems disclosed in U.S. Pat. No. 3,978,457 for MICROCOMPUTERIZE ELECTRONIC POSTAGE METER SYSTEM, in U.S. Pat. No. 3,938,095 for COMPUTER RESPONSIVE POSTAGE METER, in U.S. Pat. No. 4,301,507 for ELECTRONIC POSTAGE METER HAVING PLURAL COMPUTING SYSTEMS and in European Patent Application, Publication No. 0 019 515 for ELECTRONIC POSTAGE METER HAVING IMPROVED SECURITY AND FAULT TOLERANCE FEATURES.
Each of the electronic postage meters disclosed in the above-identified applications and patents includes a non-volatile memory for storing critical information when power is not applied to the meter. Various types of accounting information may be stored in the meter's non-volatile memory. This information includes, for example, the amount of postage remaining in the meter for subsequent printing and the total amount of postage printed by the meter. Other types of accounting or operating data may also be stored in the non-volatile memory. The function served by the non-volatile memory circuits have replaced and enhanced the functions of the mechanical accounting registers or wheels utilized in previous mechanical type postage meters.
It has been recognized that during the assembly of electronic postage meters it may be desirable to enter the serial number into the non-volatile memory of the meter upon completion of the assembly operation. It is found that this can be done in electronic postage meters. In one such arrangement, a non-volatile memory chip number is entered into the non-volatile memory and is used during the assembly of the meter. The meter itself, however, is assembled with the final serial number on the meter body still utilizing a non-volatile memory with a given chip number entered in the serial number field. When assembly and testing is completed, the final serial number is communicated to the meter. It is also noted that a flag bit can be set if the path to the serial number in the non-volatile memory is to be closed off so that the data field in the non-volatile memory occupied by the serial number cannot be written into. That is, writing into non-volatile memory data field containing the serial number is prevented. Such a system is disclosed in U.S. patent application, Ser. No. 238,331 filed Feb. 26, 1981, now U.S. Pat. No. 4,424,573, issued Jan. 3, 1984, for Alton B. Eckert, Jr. and Edward C. Duwel, and entitled "SYSTEM FOR ENTERING A POSTAGE METER SERIAL NUMBER INTO A NON-VOLATILE MEMORY FROM AN EXTERNAL CHANNEL AFTER ASSEMBLY OF THE METER".